Electric windshield wiper



July '22, 1952 A.' cHRlsTENsEN ELECTRIC WINDSHIELD WIPER 4 Sheets-Sheet 2 Filed Dec. 8, 1944 July 22, 1952 A. cHRls'rENsEN ELECTRIC WINDSHIELD WIPER Filed Dac. 8,A 1944 4 Sheets-Sheet 5 A. CHRISTENSEN ELECTRIC WINDSHIELD WIPER July 22, 1952 4 Sheets-Sheet 4 Filed Dec. 8, 1944 2% 3 y v0 m v.

ya M A m m www w? L Patented July 22, 'T952 UNITED vSTATES PATENT OFFICE ELECTRIC WINDSHIELD WIPER Alfred Christensen, Chicago, Ill., assignor to Stewart-Warner Corporation, Chicago, Ill., a corporation of Virginia Application December s', 1944, serial No. 567,248

claims. (c1. 15-25S) The present invention relates to windshield wipers and particularly to electric windshield wipers of the type operable in what may be termed a normal range of movement and which are automatically parked in a position outside of that range by the inertia of the moving parts of the apparatus. The invention is an improvement over the apparatus disclosed and claimed in. the copending application of John B. Whitted, Serial No. 463,616, filed October 28, 1942, now Patent No. 2,412,850, granted December 17, 1946, upon an Electric Windshield Wiper, and assigned to the assignee of this application.

A primary object of the present invention is to provide a new and improved, eilicient and economical electric windshield wiper.

Another object of the present invention is to provide an electric motor driven windshield wiper wherein the direction of operation of the wiper blades is controlledby a reversing switch and wherein the parking is also controlled by the reversing switch and what may be termed an automatic parking switch, both of which are operate by a single motor driven element. *Y

Another object of the present invention is to provide a novel reversing and parking control unit for an electric windshield wiper. Y

A further object of the present invention is to provide a new and improved windshield wiper operating mechanism and more specifically an operating mechanism which may be correlatedl with the novel control unit to provide .a windshield wiper which can be manufactured atlow cost and which will be satisfactory in operation and have a long, useful life.

Other objects of the lpresent invention will become apparent from the ensuing descriptiomin I the course of which reference is had tothe accompanying drawings, in which:

Fig. 1 is a fragmentary front elevational view, partly broken away, of an automobile upon which the apparatusY of the present invention is installed. In this gure the windshield wiper blades are -shown in their parked position and the phantom lines indicate the normal range of operation of the blades; v

Fig. 2 is an axial cross-sectional view through the windshield wiper blade operating motor and control unit. The iigure also illustrates the operative mechanical connections of themotor to the windshield wiper operating means;

Fig. 3 is an enlarged cross-sectional view of the motor reversing switch and its operating means, the view being taken along the line 3-3 of Fig. 2;

Fig. 4 is a view similar to Fig. `3 taken along the broken line 4-4 of Fig. 2;

Fig. 5 is a cross-sectional view taken along line 5--5 of Fig. 4;

Fig. 6 is a similar view taken 6--6 of Fig.4;. f

Fig. 7 is a transverse cross-sectional viewl taken along the line 1-1 of Fig. 2; 1 y

along the line the Fig. 8 is an axial cross-sectional view taken along the line 8-8 of Fig. 2;

Fig. 9 is an enlarged front elevational view of a rack and pinion arrangement for oscillating the windshield wiper through the means reciprocated by the electric motor;

Fig. 10 is a transverse cross-sectional lView taken along the line IIl-ID of Fig. 2; I

Fig. 11V is an enlarged axial cross-sectional view like a corresponding portion of Fig. 2 illustrating the motor reversing switch in one of its two positions; o.

Fig. 12 is a similai` View illustrating the switch in its other position;

Fig. 13 is a diagrammatic representation of the circuit connections' andthe motor reversing switch;

Figs. 14 and 15 are views similar to Figs. 11 and 12 of a modified embodiment of the invention; and

Fig. 16 is a diagrammatic representation of the circuits and control switches of the modied embodiment of the invention.

In the embodiment of the invention illustrated inrFigs. 1 to 13, inclusive, the electric windshield wiper of the present invention is illustrated as being installed in an automobile I0 and as being attached to the engine side of the dashboardor the like. It is secured in place by suitable mounting means including a plate I2 and a pair of brackets I4 supporting a combined motor and control unitv indicated as a -whole by reference character I 6. The windshield wiper is controlled by a manually operable switch I8 placed, as usual, upon Vthe dashboard so as to be readily accessible to the operator of the vehicle.

The motor 26 which forms a part of the coml bined'motor and control unit I6 is a reversible 'electric motor which, however, in accordance with one of the important features of the present invention, is adapted to impart reciprocating movement to a windshield wiper operating member indicated generally b-y the reference character `22 (see-Fig. 2) which, for convenience, will hereinafter be referred to as a rod. The reciprocating movements of the rod are utilized to oscillate the windshield wiper blades 24 through Bowden wires 25 extending from the rod to 'mechanism transforming the reciprocating ymovement to 'oscillatory movement.

The windshield wiper blades aremounted upon oscillatable supporting arms 28 and are movable by means of pinions 3U (see Fig. 9) mounted upon the arm supporting shafts 32. The pinions are oscillatedfby rackgea'rs 34 having gear teeth'a held in mesh with the pinionsby pairs of rollers 38 located on the side opposite therack` gears from the pinions. These rollersand therracks and pinions are all preferably Vsupported upon suitable supporting-means suchfas brackets 40 secured in suitable lmanner to the4 automobile. The ends ofthe Bowden wiresf26 are -adjustably secured to the rack gears as by th-e bolt and slot connections 44.

In accordance with another feature of the present invention, the arrangement of the windi shield wiper operating means is such that theV wiper blades always move in opposite directions;-

i. e., when one blade is moving in a clockwise direction, the other is moving'in a counterclockwise direction. Furthermore, the blades are parked adjacent each other so that they occupy the least noticeable position, which is near the bottom and center portion of the windshield, as clearly illustrated in Fig. l. This feature is achieved by placing one of the rack gears 34 ybelow the pinion andthe other above the pinion,

i. e., the rack gearsl are placedon opposite sides of the axes of the pinions 30. YAs a result, when the rack gears are moved, and they are moved in unison, the windshield wiper blades are oscillated in opposite directions.

The Bowden wire 216 is encased within suitable shielding or conduit means in order that it may be guided and prevented from accumulating dirt and the like. In the present instance, the Bowden wires are led through relatively small diameter tubes 46 extending from the combined motor and control unit I6 to the brackets 40. At the bracket ends the tubes are secured to the brackets by ttings 48 (see Fig. 9). At the motor ends the tubes are secured to tubular shields 50 `(see Fig. 2) projecting outwardly from opposite sides .of the combined motor and control unit and within which the windshield wiper operating vrod 22 is reciprocated. The outer ends 52 of the shields 50 are secured to the Bowden wire containing tubes 46 in suitablemanner, as by swaging. The shields are attached to the end plates 54 and 56 of the motor and controlling unit in suitable manner as by the couplings '58 to secure the flanged ends 60 of the shields therebetween and the ends of the end plates 54 and 56, respectively.

, The Bowden wires are adjustably secured to Ytermined limits. p are thusoscillated through suitable limits delining a normal operating range such as that indicated by the phantom lines in Fig. 1. The

direction of motor rotation is controlled by a reversing switch indicated as a whole by refer- Vthe reciprocable wiper blade operating rod 22 in l suitable manner. In the instant case the left (see Fig. 2) Bowden wire 26 is secured to the threaded end 62 of the rod by a tubular extension 64 swaged to the Bowden wire and threaded onto end 62, where it is locked in place by a lock nut 66. The other Bowden wire is somewhat similarly secured to the opposite threaded end 68 of the rod by a threaded extension 10 threaded onto end 60 and to the end of the Bowden wire 26. It is locked in place by a lock nut 12.

The windshield wiper operating rod 22 is reciprocated in a novel manner by the motor 20 and the element is utilized not only to operate the wiper blades but also the control mechanism which will be described shortly and which is mounted'within a housing defined by the end plate 5B of the combined motor and control unit. The rod is reciprocated by the motor shaft '|4 which is internally threaded over a portion of its length as indicated by the reference character "16 and which is mounted in spaced apart bearings "H engaging shoulders formed on the shaft to restrain axial movement of the shaft. The rod is provided with an externally threaded portion 18 yengaging the threaded portion of the hollow motor shaft and it is prevented from rotating with Vthe result that, as the motor rotates the shaft,the rod is moved axially. The rod is pre- Vvented from rotating by suitable means such as the square portion 80 passing through a square opening 82 at the outer end of end plate 54.

mechanism.

ence character 84 which is operated at desired limits of movement by the axial movement of the windshield wiper operating rod 22.

The reversing switch- 84 is preferably of the snap action type and'isoperable between two positions by an axially movable sleeve 86 (preferably made of insulating material) apertured loosely to surround an intermediate enlarged portion 88 Vof the windshield wiper` operating rod 22. The sleeve is movable between twolimiting positions indicated in Figs. 11 and 12 and which are determined by engagement of a collar-like portion of the sleeve with an insulating switch mounting plate 90 and a generally U-shaped bracket 92 secured to the mounting plate andv extending axially toward the motor and apertured as indicated by'reference character 94 (see Fig. 11) loosely to surround the innerend of sleeve 88.

The switch operatingsleeve 88 is moved between its two positions to operate switch 84 with a snap action by thelimits of` axial movement of rod 22. More specifically, the sleeve is operated upon engagement with washers 96 and 98 held in abutting engagement with the central enlarged portion 88 of rod 22 by springs |00 and |02, respectively. The spring |00 encircles a reduced portion |04 of the operating rod and abuts againstA the washer 96 and against the threaded portion 18 of the rod. In order to facilitate construction, the portion |04 is provided with a threaded end |06 whereby it may be detachably securedto the threaded portion 18. The

'I 'he springs impart a degree of resiliency to the l'operatitm of the switch operating sleeve and the spring |02, in addition, may be compressed somewhat when the bladesv move into the parking position and the blade operating'lrod movesits grestest distance toward lthe left, because of the inertia of the moving parts ofthe blade operating carrying movable switch element H0 preferably made of resilient metal such as Phosphorbronze.

It includes a pair of side end-connecting parts ||2 and a pair of centrally located opposed tongue-like portions I4, the inner ends of which engage grooved metal bearings ||5 situated in opposed grooves ||8 at the topland bottom sides of the lswitch operating sleeve 86. The snap actionis provided by flexing the tongue-like por'- tions I 4 so that they are over center with respect to the interconnecting outer sides I 2 in the two positions of theswitch,l which are determined by opposed fixed contacts engageable with the movable contacts |20- and |22 carried at opposite ends of-'the movable switch elementv ||0.

The Viixed contacts 'associated vwith movable Contactv |20,'indicate'd by reference characters |24 and |26, are Vmounted upon conducting supporting brackets |28 and |30, respectively (see Figs. 3 Yto 6, inclusive). These' two brackets are secured to the insulating plate Boby rivets'4 |32 and'termi'nal bolts |34 and |35, respectively. The Stationary contacts associated with movable con- 123613122, indicated by ref'erenceycharacters |38 andr|40 Vare secured upon conducting terminal brackets |42 and.Y |44, respectively. The brackets areA secured to theinsulating 'mounting -plate 90 by` rivets |32and terminal bol-ts |48V and |48, respectively. y

The motor 20I may beiof any suitable reversible type.. being a'direct current motor having-an arma-ture |50 and a pair-of field windings |52-and |54 adaptedy selectively tof-be energizedto rotate'the motor rotor in opposite directions. One terminal of the armature is connected to ground through conductor |56 and the other to the junction of the two eldwwindings. rv'l-he other terminals of windings |52' andfili: are connectedA by Conduc-r tors'li and |162 tensed-contacts |40 and |38, respectively, of theY reversing switch. Fixed contact |26 is connected through-,conductor |64 and a switch |66, vwhich may be the conventional switch, tog-a batteryv I 68 or other` suitable source'of power having one terminal grounded'through conductorl l0. .The otherfixed Contactv |24 is connected to comiuctorl |68 through the manually operable switch |8 which-is closed ywhenever'the windshield wiper is in operation.

lWhenn the windshield wiper isto be placed in operation, the ignition switch |66-isrst closed to supplypower to the reversing-switch. The re- Versing switch, in the parked position of the blades, occupies the position in which itis illustrated in Figs. :2, 1l and ,1.3. Under these conditions "and with the manual control switch i8 open, no'powerr is suppli-edito the motor-with the result that the motor remains inoperative.

To energize the vmeter to move the wiper blades, it is necessary only to close switch |.S. thisis done,the motor winding tim and the ar mature |50 are supplied with power -from the battery through the reversing rswitch-and the now closed manually operable switch |0. As a result, the motorisrotateddn one direction to move ythe windshield v.operating rod 22V axially from its eXtreme left'v position toward the right. Such movement of rod-effects movement of the windshield wiper blades `through the Bowden wire-connections andthe rack and pinion gearing. The reversing switch remains in its indicatedlposition until the switch operating sleeve 86 is Vengaged by washer 96. Some slight further movement of element22 moves the sleeve 8B toward' the right until the over-centermechanism snaps the movable switch element to its other.,position-the-position in which it is shown in .Fig.-l2. Immediately -the winding |514 is deenergizedrand Winding |52 is energized to rotate the motor' in the opposite direction. As a result, the operating rod is moved axially in the opposite direction until washer 88 engages the opposite end of sleeve 86 to move it to theleft. When the sleeve moves to the left to move the over-center mechanism beyond centerJ the switch is returned to its initial position. Consequently, the windshieldV wiper blades are operated through what maybe termed a normal operatingjrange' by reciprocation of the operatingr element l22`between limits determinedV by the actuation ofthe reversing switch 84 between its two positions `as-described-above.

Thefvmechanism of the present'inventionutilines the inertia of the moving parts of the motor and associated mechanism to move the wiper bladesto .their parked position. Assuming `that the movable'contacts |2 and |22'are in engagement with-stationary contacts |28 and.; fili, i. c.,

It is, howevere illustrated (in Fig. 13) as.

When

so thatwinding lliscenergized and the'l-rodzZ-Z is moving towardA ther left. andi-thata fsw'itch'-,v |l 8; ,is then opened. 'Under' these conditions; theropening; of theV switch haswnoveect because. no;circuit is closedvacross contacts 421i and |112.V :Themotor continuesy to rotate'- to 'move' the rod; to :the left until washer 88" engagescsleeve 86 and moves: it to the left. When thisifoccurs the switch element |10 is-I moved to 'deenergize :winding |52 and: to connect Ya circuit yacross contacts. |2f4rand S |542-, However, the motor does not :reverse because switch I8 is now open, so Ythatztii'e"closureothe circuit y:across the :contacts-f does-not energize winding l 54. As 19,: resultrthe. inertia of. thev moving parts moves .the wiperfb-ladesbeyond Athe normalem-nge ormovementzan'd into their. parked position. 1 l -x 1n ,the embodiment of .the invention illustrated iny Figs. 14, 151. and 16., the control. is sofconstruct-y ed and arranged-,that the opening ofthe" manual'- ly operable switch I8 atany time `willnot'de-v energize the motor until the switchzwiper blades havefbeen properlyparke'd. This is not Vtrueof the previously describedf'embodiment.of` thai-invention vas it maybe notedff-ronr Fig.;l3'" 'that' if switch v'|18 ist opened with thereversingf switch in its indicated position; the opening,l of' theJsWitch will immediately deenergizethem'otor.

In` the' now about to be *described* embodiment,` an Aauxiliary switch, which may be called ran automatic'parkin'g switch and which is indicated by reference character |00, is utilized Nto maintain an energizing circuit :to thev motor despite `the openingof the manual switch I8 until: such time thatthemotor is rotating .in` the proper direction: to Vpark .theswitch' blades. -The parking switch isarran'ged to be actuated by the windshield Wiper operating 'rod |120 and preferably substantially simultaneously withv or slightly beforethe kreversing switch. vThe isecon'd embodiment has not been :illustrated in 'full because the apparatus 'may remainfsubstant'iallyf the same vas that 'heretofore described, kexcept -for the'addition of the: parking lswitch and theoperatingmeans therefor.` A x 'The'parkng f switch includes a movable .con`` tact- |82 vmounted .upony a resilient switch yblade |84 biased to.' move. the contact into 1 engagement with a fixed contactzl 'condu'ctively connected to `contact 24 as: through a common'terminal bracket |88'. Therbladel A|8111 is centrallywaper-l tured ,as indicated'by reference lcharacter |99 so as loosely to iit about an'extendedportion"|92 ofthe Aswitch operatingsleeve 86; The parking switch is moved-from itscircuit closing to `its circuitY opening position when the windshieldy wiper blades move in parking direction-byan enlarged sleeve |94 loosely surroundingportion 88 of element 22 and interposed between sleeve 86 andthe washer 88.l The circuit arrangement for. the second em# bodiment of -theipresent invention is `illustrated in Fig. 16, to which reference is now had. Froml this itmay be noted thatthe Vcircuit is substani tially the same as that of Fig; 13, except for the addition of `the .parking switch having ,itsfxed contact |86 conductively connected to xedfcontact `'|24 of thereversing switchrand havingyits movable switch blade connected to conductor;|.6.4 through branch conductor |96. The `parking switch is thus'` in parallel :with the manuallyiorp erable switch |8.

When the ignition and manualrswitchesare open, the windshield wiper bladesare parkedand the operating elements are in". the positionslin whichthey are shown in Figs. 14 and 16. To place the windshield wipers in operation, it is necessary to close the ignition switch |56 and the manually operable switch I8. When they have been closed, winding |54 is energized through these two switches and the reversing switch and the motor move the reciprocating windshield wiper operating rod 22 toward the right. Initial movement to the right'permits the parking switch |84 to close, but such closing has no eiiect as the switch is connected in parallel with the previously closed switch I8.

When the windshield wiper blades'reach thel limit of their movement, the reversing switch is operated to deenergize winding |54 and to energize winding |52. The motor operates now in the reverse direction and when the limit of movement is reached, the rod 22 operates both the reversing and auxiliary switches, preferably substantially simultaneously, the reversing switch being operated by switch 86 and the auxiliary switch by sleeve |94. The opening of the parking switch has no eiect upon the operation because switch I 8 remains closed.

In thisembodiment of the invention, the time of opening of switch I8 is not of material moment because the control is such that the motor is energized until it is rotating in the proper direction so that its momentum will properly park the wiper blades. .If the manually operable switch I8 is opened with'winding |52 energized, i. e., when the motor is operating in the proper direction for parking, the motor remains' energized through the reversing switch until both the latter and the parking switch are opened and occupy the' positions in which they are shown in Fig. 16, after which the` inertia drivesy the blades to their parked positions. If, on the other hand, the Yswitch I8 is opened when the motor is rotating in the wrong direction for'parking, i; e., with the reversing switch in the position shown in Fig. -16 and with the parking switch'closed, then the parking switch maintains the motor energizing circuit even though switch I8 is opened. Consequently, the motor willrun until the reversing switch is opened to energize winding |52 after which the motor will run until both the reversing switch and the parking switch are operated ytothe positions shown in Fig. 16.

- While I' prefer to employ the form and arrangement of the parts as shown in the drawings and as above described, the invention is not to be restricted'thereto except so far as the claims may be-'so limited, it being understood that changes might well be made in the'iorm and arrangement of the parts without departing from the spirit of the invention.

'Iclaim: i' s1,-1'A windshield wiper including a pair of oscillatable blades operable by an electric motor controlledfby va reversing switch, including in com-1 bination,y means reversibly rotated upon reverse rotationV of' the motor, reciprocable means operativelyconnected to said first mentioned means and directly reciprocated longitudinally by' said firstmentioned meanswhenithe latter rotates, means operable by said second mentioned means Y at'predetermined spaced apart longitudinal positions for operating said reversing switch, rack and pinion 'gear means arranged to oscillate said blades in'opposite angular directions in response tovreciprocating movement in one direction, and means. 'coimec'ting said rack gear' means to: said reciproc'atedmeans: l f f 12;.;Awindshield1wiper operableiby iastationary 8 electric motor controlled by a reversing switch, a manually operable switch and an automatic parking switch parallel to the manually operable switch, including in combination, an internally threaded shaft reversibly rotated upon reverse rotation of the motor, an externally threaded member within said shaft reciprocated longitudinally by said shaft, reversing switch operating means operated by said reciprocated member at predetermined limits of movement thereof, and parking switch operating means operated by said reciprocated member at one of said limits of movement.

3. A windshield wiper as claimed in claim 2, wherein said shaft is the motor shaft.

4. An electrical windshield wiper of the type operable by a stationary reversible electric motor controlled by a two-position reversing switch, in-

cluding in combination, means for operating the"v reversing switch whereby the motor operates the wipervr between normal limits of movement, and

manually controlled switch means in circuit with the reversing switch controlling the energization of the motor adapted to condition the motor for deenergization by the reversing switch when the switch is operated to one position by said motor operated means, whereby the inertia of the motor and parts driven thereby are capable of parking the wiper in a position beyond'thel normal limits ofv movement of the blade, a parking switch in parallel with the manually controlled switch means for maintaining a circuit,

to the reversing switch independently of the manually controlled switch means when the reversing switch is in its other position, and a single member reciprocably movable in opposite directions as the motor rotates for operating both said reversing switch operating means and said parkingswitch.

5. A windshield wiper operable by a stationary reversible electric motor controlled by a reversing switch, including in combination, over-center' mechanism foroperating said switch with a snap action, an element reversibly rotated by reverse rotation of the motor, a longitudinally extending member having a driving connection to cause it to be reciprocated by rotation of said element alternately in opposite directions, means operable by the reciprocated member at two predetermined spaced apart longitudinal positions for operating said over-center mechanism, said last named means including a pair of springs movable with respect to said reciprocated member and said over-center mechanism and arranged to store energy for the operation of the over-center mechanism, whereby said over-center mechanism is effective to operate the switch with a snap action, a wiper parking control switch, and means operable by said reciprocated member at one of its said positions for operating said control switch.

ALFRED CHRISTENSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

